There are two primary types of gas-fueled pocket lighters presently available. The first type of gas-fueled device utilizes a post-mix burner. Post-mix burners pull oxygen for combustion from the air surrounding the gas outlet. This combustion type is characterized by a low velocity, low temperature yellow flame sometimes referred to as a traditional or lazy flame.
A second type of gas-fueled device is a pre-mix burner. This type of burner pulls oxygen for combustion through holes in the base of the burner and combines the oxygen and fuel prior to combustion. This combustion type is characterized by a high velocity, blue flame. These burners, by virtue of their improved efficiency, provide higher flame temperatures, and more complete combustion. The devices are commonly referred to as blue flame, torch flame, or invisible flame, lighting devices.
There are two primary ignition systems that are typically used with gas-fueled cigarette or pocket lighters. The first type is the flint and wheel ignition mechanism. A hardened striking wheel is rotated against a flint made of a pyrophoric material. The engagement of the striking wheel with the flint produces a spark that ignites the fuel as it leaves the gas outlet. Another type of ignition system is piezoelectric. In this type of ignition system, a high voltage charge is generated when a crystal is struck. A spark is created when this charge jumps across a preset gap between an electrical contact and the gas nozzle (which is constructed of a conductive material). This spark ignites the gas as it leaves the nozzle.
The pre-mix burners offer advantages over post-mix burners including better efficiency of combustion, higher heat, and higher velocity, which makes the flame more stable and less likely to be blown out by the wind. The flint and wheel type ignition offers some advantages over piezoelectric ignition systems including being more reliable and consistent, and less costly to produce. Attempts to combine the pre-mix burner with flint and wheel ignition have met the following difficulties. Because of the velocity of the pre-mix burner, it is difficult to ignite the air/fuel mixture with flint and wheel type ignition systems. Also, the dust and debris generated by the flint and wheel ignition system has a tendency to accumulate and clog the air orifices and the gas orifice on the pre-mix burner.
To overcome the above drawbacks, devices have been developed to incorporate a dual i.e., separate burner approach in combination with the flint and wheel ignition. These devices generally offer the following features. First, the device can provide both a post-mix and a pre-mix flame from the same device or lighter, but using separate burners. Some of these devices utilize a flint and striking wheel and others use piezoelectric ignition. In addition, some devices ignite one burner and then utilize the existing flame to ignite the other burner. The dual burner approach suffers from drawbacks including increased complexity, and therefore increases the cost with an adverse effect on reliability. Accordingly, what is needed is a gas operated pocket lighter that combines a single burner capable of operating as a pre-mix burner along with the flint and wheel ignition system.